Display screens are the primary visual display interface to a computer. One problem with these visual display screens is that they are limited in size, thus presenting a challenge to user interface design, particularly when larger amounts of information is to be displayed. This problem is normally referred to as the “screen real estate problem”.
Well known solutions to this problem include panning, zooming, scrolling or combinations thereof. While these solutions are suitable for a large number of visual display applications, these solutions become less effective where the visual information is spatially related, such as maps, newspapers and such like. In this type of information display, panning, zooming and/or scrolling is not as effective as much of the context of the panned, zoomed or scrolled display is hidden.
A recent solution to this problem is the application of “detail-in-context” presentation techniques to the display of large surface area media, such as maps. Detail-in-context presentation techniques take on many forms and are useful for displaying large amounts of information on limited size computer screens, and are becoming more important with the increased use of hand held computing devices such as personal digital assistance (PDA's) and cell phones.
Now, in the detail-in-context discourse, differentiation is often made between the terms “representation” and “presentation”. A representation is a formal system, or mapping, for specifying raw information or data that is stored in a computer or data processing system. For example, a digital map of a city is a representation of raw data including street names and the relative geographic location of streets and utilities. Such a representation may be displayed visually on computer screen or printed on paper. On the other hand, a presentation is a spatial organization of a given representation that is appropriate for the task at hand. Thus, a presentation of a representation organizes such things as the point of view and the relative emphasis of different parts or regions of the representation. For example, a digital map of a city may be presented with a region magnified to reveal street names.
Detail-in-context presentations allow for magnification of a particular region of interest (the “focal region”) in a representation while preserving visibility of the surrounding representation. In other words, in detail-in-context presentations focal regions are presented with an increased level of detail without the removal of contextual information from the original representation. In general, a detail-in-context presentation may be considered as a distorted view (or distortion) of a portion of the original representation where the distortion is the result of the application of a “lens” like distortion function to the original representation. A detailed review of various detail-in-context presentation techniques may be found in a publication by Carpendale, Marianne S. T., titled “A Framework for Elastic Presentation Space” (Burnaby, British Columbia: Simon Fraser University, 1999) and incorporated herein by reference.
Thus, detail-in-context presentations of data using techniques such as Elastic Presentation Space (“EPS”) are useful in presenting large amounts of information on limited-size display surfaces. Detail-in-context views allow magnification of a particular region of interest (the “focal region”) in a data presentation while preserving visibility of the surrounding information. Development of increasingly powerful computing devices has lead to new possibilities for applications of detail-in-context viewing. At the same time, the development of new compact, mobile computing platforms such as handheld computers, typically with reduced computing performance and smaller display surfaces as compared to desktop or mainframe computers, has motivated research into alternate implementation techniques and performance improvements to detail-in-context data presentation technologies. Consequently, one shortcoming of current EPS graphics technology and detail-in-context presentation methods is that being computationally inefficient, they are not optimized for newer compact, mobile computing platforms (e.g. handheld computers) that have reduced computing power. Considerable computer processing is required to distort a given presentation so as to produce a detail-in-context “lens”, and to move the lens through the data with adequate performance to provide an acceptable level of interactivity to the user.
A need therefore exists for a method and system that will allow for the effective implementation of EPS graphics technology on computing platforms having variable levels of computing power. Consequently, it is an object of the present invention to obviate or mitigate at least some of the above-mentioned disadvantages.